341 research outputs found

    An intermediate value theorem in ordered Banach spaces

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    We consider a monotone increasing operator in an ordered Banach space having uu_- and u+u_+ as a strong super- and subsolution, respectively. In contrast with the well studied case u+<uu_+ < u_-, we suppose that u<u+u_- < u_+. Under the assumption that the order cone is normal and minihedral, we prove the existence of a fixed point located in the ordered interval $[u_-,u_+].

    Conflict of Laws

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    Conflict of Laws

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    The second Konus-Wind catalog of short gamma-ray bursts

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    In this catalog, we present the results of a systematic study of 295 short gamma-ray bursts (GRBs) detected by Konus-Wind (KW) from 1994 to 2010. From the temporal and spectral analyses of the sample, we provide the burst durations, the spectral lags, the results of spectral fits with three model functions, the total energy fluences and the peak energy fluxes of the bursts. We discuss evidence found for an additional power-law spectral component and the presence of extended emission in a fraction of the KW short GRBs. Finally, we consider the results obtained in the context of the Type I (merger-origin) / Type II (collapsar-origin) classifications.Comment: Accepted to the Astrophysical Journal Supplement Series (7 Figures, 8 Tables

    The role of apical support and rectal mucosal prolapse excision in successful treatment of rectocele combined with perineum descending: short-term and follow-up results

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    The aim of the research was to improve the results of surgery treatment of posterior compartment of pelvic floor using abdominal sacrocolpopexy and stapled trance-anal resection (STARR

    The advantages of the abdominal sacral colpopexy combined with stapled trance-anal resection of the rectal mucosal prolapse (STARR) for the surgical treament of perineum descending syndrome

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    The problem of pelvic organ prolapse in women is still actual, because of high frequency of this pathology. Several surgical techniques have been suggested for pelvic descending syndrome treatment. But a large number of complications, unsatisfactory anatomical and functional results of suggested methods force to look for other solutions of the proble

    Interface effects in spin-dependent tunneling

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    In the past few years the phenomenon of spin dependent tunneling (SDT) in magnetic tunnel junctions (MTJs) has aroused enormous interest and has developed into a vigorous field of research. The large tunneling magnetoresistance (TMR) observed in MTJs garnered much attention due to possible application in random access memories and magnetic field sensors. This led to a number of fundamental questions regarding the phenomenon of SDT. One such question is the role of interfaces in MTJs and their effect on the spin polarization of the tunneling current and TMR. In this paper we consider different models which suggest that the spin polarization is primarily determined by the electronic and atomic structure of the ferromagnet/insulator interfaces rather than by their bulk properties. First, we consider a simple tight-binding model which demonstrates that the existence of interface states and their contribution to the tunneling current depend on the degree of hybridization between the orbitals on metal and insulator atoms. The decisive role of the interfaces is further supported by studies of spin-dependent tunneling within realistic first-principles models of Co/vacuum/Al, Co/Al2O3/Co, Fe/MgO/Fe, and Co/SrTiO3/Co MTJs. We find that variations in the atomic potentials and bonding strength near the interfaces have a profound effect resulting in the formation of interface resonant states, which dramatically affect the spin polarization and TMR. The strong sensitivity of the tunneling spin polarization and TMR to the interface atomic and electronic structure dramatically expands the possibilities for engineering optimal MTJ properties for device applications.Comment: 22 page

    Spin-dependent tunneling from clean and oxidized Co surfaces

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    Transmission through a sufficiently thick vacuum barrier is factorized in the product of two ‘‘surface transmission functions’’ and a vacuum decay factor. Based on this factorization, we study the spin polarization of the tunneling current from clean and oxidized (1 1 1) FCC Co surfaces through vacuum into Al. The conductance is calculated using the principal-layer Green’s function approach within the tight-binding LMTO scheme. We find that for typical vacuum barrier thicknesses the tunneling current from the clean surface is dominated by minority-spin electrons. A monolayer of oxygen on top of the surface completely changes the shape of kll-resolved transmission and makes the tunneling current almost 100% majority-spin polarized
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